Where do the extra volts go on a regulated 12v system?

[Tinkerer]

If a regulator pulls say 16V off the alternator down to say 14V going into the battery, what happens to the excess 2 volts?<br /><br />If it's not a good idea to run an alternator that's not connected to a charging system because the inability to discharge can damage the coils etc, wouldn't it harm the alternator over the long term if a couple of volts are always stopped from leaving the alternator? <br /><br />Or do the excess volts just disappear somehow?<br /><br />No prizes for guessing I have no idea how a regulator or charging system actually work, although I understand what they do.

 

[beniam]

Re: Where do the extra volts go on a regulated 12v system?

Tinkerer<br />All energy you generate goes somewhere<br /> Some voltage loss goes to resistance ("friction") in the transmission process, whether at a junction, or through the length of the wire. This will show up as heat(warm wire or junction).<br />Some will go into your battery (storage of electrical energy), to convert into chemical potential energy, for you to use when you need it. After the battery is full, some will go into your battery as surplus, and start splitting water into hydrogen and oxygen.<br />If you multiply amps times volts, you will get watts, a measure of the amount of energy you produce (for example 60 watt light bulb).<br />Hope to not have confused you more.<br />Be happy, enjoy life and boat lots. Batavier

 

[beniam]

Re: Where do the extra volts go on a regulated 12v system?

Tinkerer<br />I apologize, I missed some of your question. <br />Extra energy in the alternator goes to heat using the diodes. If not connected to a battery to even out flow, your diodes will be over powered and blow. Batavier

 

[Dunaruna]

Re: Where do the extra volts go on a regulated 12v system?

You bored Tink?<br /><br />As the alternator spins faster it creates more and more voltage, if unregulated it would eventuate in a meltdown - literally.<br /><br />Two different ways to regulated voltage, the most common is to switch the alternator on/off depending on demand, it happens very quickly, you won't see it with a normal multi-meter. The second way is to dump excess voltage to ground (that's 'earth' to you and me). <br /><br />In the old days, regulators converted voltage into heat, that's why they had big heatsinks attached.<br /><br />In Australia, if you have your house solar powered, you can sell excess voltage back to the national grid.<br /><br />Now, do you want details or will that do?<br /><br />Aldo

 

[Tinkerer]

Re: Where do the extra volts go on a regulated 12v system?

Thanks all.<br /><br />I dunno how an enquiring mind searching the cosmos for great truths in physics could be mistaken for being bored. <br /><br />I might go out and start up my motor in the dark to see if I can see the excess volts leaping from the alternator.

 

[jtexas]

Re: Where do the extra volts go on a regulated 12v system?

Electricity for dummies (remember I'm just an accountant with an irrational curiosity about electricity):<br /><br />Voltage is nothing more than a difference in the state of charge between two points (surfaces? terminals? sorry, terminology escapes me). One terminal is willing to give up electrons, the other is hungry for 'em. Add a conductor to create a circuit & they will flow (that's called current). If the conductor is too small or otherwise doesn't conduct very well ("inefficient"), inadequate gauge wire, or a light bulb filament, for example, you will have an electron stampede, like rock & rollers trying to get into a Who concert. That creates friction which makes the conductor get hot. If it's a light bulb filament, you see the heat as light; if it's an inadequate gauge wire, you see it as smoke when the insulation starts to melt, or a fuse will blow, disrupting the circuit. <br /><br />Volts that get converted to heat energy leave the circuit never to be seen again (well the actual electrons don't just disappear, but that's a whole nuther subject). <br /><br />The efficiency with which a conductor is able to conduct is referred to as resistance, more efficient = low resistance, less efficient = high resistance.<br /><br />How much current (measured as "amps") is in a circuit depends on the voltage (measured as "volts") and resistance (measured as "ohms"). Electricians for some reason use the letter "I" to represent current, "V" for voltage and "R" for resistance.<br /><br />I = V / R (the Iguana sees the Vulture over the Rabbit)<br />R = V / I (the Rabbit sees the Vulture over the Iguana)<br />V = IR (the Vulture sees the Iguana & Rabbit side by side)<br /><br />That these relationships always hold and can be measured fascinates me. <br /><br />I know this is a very simplistic explanation. <br /><br />About current: it's not that electrons enter one end of the wire & speed along at the speed of light to the other. It's more like a water hose full of marbles; one drops out the end creating a space, the next one moves up, and so on. "Current flow" is actually defined as the opposite direction of electron flow, believe it or not, it's the direction of "hole flow." Obviously this system was not designed by accountants!<br /><br /><br />"Resistance is futile" (Seven of Nine)

 

[levittownnick]

Re: Where do the extra volts go on a regulated 12v system?

jtexas noted that voltage is represented by the letter V. It is also represented by the letter E (for Electromotive force), therefore you may use the letters V or E interchangeably (whatever suites your mood or the mood of the author).<br />Voltage can't be seen, (but you sure can feel it if it is large enough) it can be measured or represented on a display (scope).<br />Part of the story of the alternator (generator) is that a regulator is used to control the output voltage of the alternator ("part of the story"). The regulator acts on the current in the "field" coils of the alternator. The stronger the field, the greater the voltage out of the alternator "if" the alternator is spinning. The greater speed of rotation of the alternator, the greater the voltage out, the number of turns of the armature (stator in this case) the greater the voltage out, but the number of turns is fixed when the machine was built, so that is not a variable. There are other factors that don't have to be considered here that are not variables. Because the regulator can have only partial control of the alternator,s output voltage, the alternator must be constantly connected to a load to insure that it does not output a voltage higher than other loads connected to it can tolerate, most significently, the vehicle's computer among other items. In theory, without a load the output voltage of the alternator could double!<br />Therefore never disconnect the battery if the engine is running.<br />The state of charge of the battery has a direct effect on the battery's "resistance". (Remember Ohm's law from jtexas above.) If you could know the battery's resistance at any particular time, you could calculate the current from the alternator into the battery by knowing the difference in voltage between the alternator and the open circuit battery voltage. (The battery resistance is not linear under all conditions.)<br />(The normal regulated output voltage is about 14.2 Volts.) Voltage drop in the system if a function of current draw and the various resistances in the circuit. The higher the current (Amps) the higher the voltage drop. Since the components (wire) of the system are fixed, the resistance is constant. Multiplying this constant by the current gives the voltage drop. Sounds easy, but each component must be analyzed separately.<br />Good Luck - Keep on Boating.

 

[ED21]

Re: Where do the extra volts go on a regulated 12v system?

I always thought the excess voltage was stored in the electronic parts as smoke to be released at the most inopportune time. <br />At least that's my experience.

 

[chuckz]

Re: Where do the extra volts go on a regulated 12v system?

jtexas,<br /><br />Apparently accountants are smarter than Ben Franklin When Ben did his first experiments with electricity he needed to defined current flow. He had a 50/50 chance of getting it right but he got it wrong. So conventional current flow is plus to minus. However, a physicist knows that the negative particles do the moving and not the positive particles so they know electron flow is from negative to positive.

 

[Paul Moir]

Re: Where do the extra volts go on a regulated 12v system?

In the case of an outboard's alternator (which we may be talking about here), the regulator has no control over the alternator since it uses permenant magnets glued to the flywheel rather than a controlable feild. My understanding of these regulators is that they simply dump the excess which is why they need to be water-cooled and such, even though they can only supply a few amps.

 

[beniam]

Re: Where do the extra volts go on a regulated 12v system?

Wow, and I thought I did not have a life. Aaaawsome.Eeelectrifying. Getting a real charge out of this. Batavier

 

[levittownnick]

Re: Where do the extra volts go on a regulated 12v system?

Note to Ed.<br />Search this forum under smoke theory. I found it very informative.

 

[jtexas]

Re: Where do the extra volts go on a regulated 12v system?

Originally posted by L.I. Chuck:<br /> jtexas,<br /><br />Apparently accountants are smarter than Ben Franklin When Ben did his first experiments with electricity he needed to defined current flow. He had a 50/50 chance of getting it right but he got it wrong. So conventional current flow is plus to minus. However, a physicist knows that the negative particles do the moving and not the positive particles so they know electron flow is from negative to positive.

<br /><br />I guess the designation of "plus" and "minus" were also arbitrary.<br /><br />Unless you go way into higher math, numbers are really quite predictable: add 2 to 5 you will always get 7. The fact that a powerful natural phenomenon like electricity can be described in the simplest arithemetic terms just amazes me. I mean the linear relationship between and among current, voltage and resistance (as contrasted with the relationship between interest rates, the money supply, and the CPI). And don't get me started on semiconductors!<br /><br />I understand that an "alternator" generates alternating current which must be rectified by four carefully placed diodes before it is of any use to the battery. So, on an outboard, say for example, a 3-cylinder 'rude, when you say "alternator" are you referring to the whole electricity-generating function, all the stuff between the magnets on the flywheel and the powerpack? It has to provide juice to fire the plugs, right? Does that require AC, or is it downstream of the rectifier? When you say "regulator" that's not the same as rectifier is it?<br /><br />nick, from your description it sounds like the battery functions sort of like a big capacitor.

 

[chuckz]

Re: Where do the extra volts go on a regulated 12v system?

The alternator is the magnets and the stator.<br /><br />A rectifier converters AC to pulsed DC.<br /><br />A regulator controls the voltage output.<br /><br />A battery is a charge storage device so it can be described as a huge capacitor, I just can't calculate how many farads.<br /><br />The spark is created from interuupting currrent flow through the coil. So pulsed DC is sent to the coils.<br /><br />Unlike mechanical engineering, in electrical engineering everything can be precisely defined mathematically. Ohm's law is probably the simplest example. When you start discussing AC and RF theory, the relationships are not the nice linear relationships you find with DC.

 

[18rabbit]

Re: Where do the extra volts go on a regulated 12v system?

It's voodoo.<br />

 

[jtexas]

Re: Where do the extra volts go on a regulated 12v system?

Thanks, Chuck, now it's just a dark gray box, instead of a black box. I'm still a bit fuzzy on the spark plug bit, but that's about all I can tolerate today. <br /><br />Funny how engineers so rarely get curious about accounting.

 

[Tinkerer]

Re: Where do the extra volts go on a regulated 12v system?

Originally posted by Paul Moir:<br /> In the case of an outboard's alternator (which we may be talking about here), the regulator has no control over the alternator since it uses permenant magnets glued to the flywheel rather than a controlable feild. My understanding of these regulators is that they simply dump the excess which is why they need to be water-cooled and such, even though they can only supply a few amps.

That's what I'm talking about, specifically my unregulated '67 HP V4 Evinrude 6 amp system. I was pondering what would happen to the excess volts (16.7v at 1500rpm upwards) if I put some sort of regulator on it and then got to wondering about where the excess energy goes on any regulated system, 'cos all energy has to go somewhere.<br /><br />Paul, your post ties in with what I think was also your post in an earlier thread of mine about my alternator putting out too much juice, where you (or maybe someone else) said that on unregulated systems like mine the battery acts as the regulator.<br /><br />If I've got it right, the excess voltage that my unregulated system puts out goes into the battery as electrical energy, but when the battery is fully charged the excess over what the rest of system needs is converted to heat energy and dissipates into the atmosphere with the battery acting as a heat exchanger?<br /><br />Following on from Dunaruna's post about the excess going to ground, if I had a regulator that grounded back to the motor would that just dissipate the excess by grounding it or is that somehow a bad solution?

 

[levittownnick]

Re: Where do the extra volts go on a regulated 12v system?

jtexas<br />Sort of like a battery is a good description. I does smooth the output voltage - like a capacitor would. It also has some regulation functions. I'm not sure where the two differ except when you get to A.C. In the case of A.C., the capacitor's impedance "Z" is inversely propertional to frequency. That is it's effective resistance decreases as frequency increases. But since we were talking about D.C., who cares, except for possibly Batavier.

 

[jtexas]

Re: Where do the extra volts go on a regulated 12v system?

16.7v at 6 amps = 2.78 ohms of resistance (the Rabbit sees the Vulture over the Iguana); that's the R of the battery and cables, right? Is that not also 100.2 watts?<br /><br />A voltage regulator contains resistors made of some kind of space-age carbon composite that can dissipate heat, then you add a heat-sink & water source if needed, you basically just burn up however much voltage you don't want passed along, right? and maybe capacitors to protect against under-voltage?<br /><br />"goes to ground" (or for our friends down under, "goes to earth"). Grounding to the engine block just completes the circuit back to the battery, right? So as the battery recharges, resistance increases? Therefore, if the voltage is held constant, the amperage decreases?<br /><br />How'd I do?<br /><br /><br />p.s. as the rpms decline, voltage decreases, right? assuming R is constant (or changing only a little) does current increase? up to the alternator's design maximum 6 amps? at which point, what, V can't decrease anymore? <br /><br />or current turns around & goes the other way? no, that can't be right...

 

[BoatBuoy]

Re: Where do the extra volts go on a regulated 12v system?

I think of volts this way. If the water pressure supplying my house is 120 psi, I put a pressure reducer on bringing it down to 70 psi. Where does the other 50 psi go?